Perylene-diimides (PDIs) are outstanding versatile organic chromophores. They demonstrate exceptional thermal and photochemical stability, strongly absorb visible light, and show high fluorescence quantum yields. PDIs have been utilized as industrial dyes, electronic materials, sensors, photovoltaics, and building blocks for light-harvesting and artificial photosynthetic systems. Importantly, photophysical and redox properties of PDIs can be conveniently modified through substitution in the aromatic core at the positions 1, 6, 7, and 12 (bay region). Substitutions at bay positions and expansion of the PDI core are usually carried out starting from the halogenated derivatives, particularly brominated PDIs.
Doubly reduced aromatic compounds, aromatic dianions, have been extensively studied due to their fundamental importance in understanding aromaticity, m-delocalization, and electron transfer. Most aromatic dianions strongly absorb visible light to reach highly energetic excited states, allowing access to high energy electron transfer reactions. The excess charge on aromatic dianions makes them very reactive toward oxidants and protic solvents, especially water.
There is a need in the art to develop compounds having new electronic properties for use as industrial dyes, electronic materials, sensors, photovoltaics, supercapacitors and building blocks for light-harvesting and artificial photosynthetic systems.
Almost all functional materials produced today are held together by irreversible covalent bonds. Such conventional materials usually require elaborate processing and are difficult to recycle. The adaptive properties of noncovalent materials allow for easy processing, facile recycling, self-healing, and stimuli responsiveness. However, the poor robustness of noncovalent systems has hampered their use in real-life applications. While covalent bond strengths are on the order of 100-400 kj/mol, typical noncovalent bond strength normally span values ranging from 5 kJ/mol (e.g. for van der Waals forces) to 50 kJ/mol (e.g. in hydrogen bonds). Seminal research has shown that more robust supramolecular systems are feasible, for example, in supramolecular polymers based on multiple hydrogen bonds between self-complementary molecular building blocks. Whereas such multiple hydrogen bonding motifs are useful for achieving strong binding in organic solvents with low polarity or in solid state, their stability drastically decreases in the presence of more polar media, especially in water.
Using water as the basis of noncovalent materials is particularly intriguing. Water is readily available, inexpensive, safe, and environmentally friendly. Because water is the basis of biological systems, it has been used for developing biocompatible materials such as artificial tissues. Moreover, achieving highly robust noncovalent materials might be especially feasible for water-based systems, since water enables exceptionally strong solvophobic (i.e. hydrophobic) interactions.
This invention relates to creating robust noncovalent arrays by utilizing strong hydrophobic interactions in aqueous media. Such aqueous assemblies are based on aromatic amphiphiles with extended hydrophobic cores, and exhibit fascinating properties, including robustness, multiple stimuli-responsiveness, and pathway-dependent self-assembly. These water-based noncovalent materials have the potential to replace or complement conventional polymer materials in various fields, and to promote novel applications that require the combination of robustness and adaptivity.